The present invention relates to a displacement detector.
Recently, a displacement detector (or an encoder) has been widely used as one of apparatuses measuring a displacement. The displacement detectors of various detection types such as a capacitive type and an optical type are used. For example, a linear encoder that is an example of the displacement detector includes a scale and a detection head moving along the scale, and detects a displacement between the scale and the head.
In general capacitive displacement detectors, it is known that an undesirable transmission signal interferes with a received signal and thereby crosstalk occurs when detecting the displacement. Therefore, accuracy of displacement detection deteriorates. On the other hand, a method for correcting the crosstalk has been proposed (Japanese unexamined patent publication No. 2-269908). In this method, the crosstalk is cancelled at a reception electrode by adjusting an amplitude of a signal having a phase opposite to a phase of a signal input through a capacitance of an unnecessary path and inputting the adjusted signal as a correction signal to the reception electrode.